1. Field of the Invention
The invention mainly relates to a novel microorganism strain Lactobacillus rhamnosus GM-020 and its use for treating obesity or complications thereof.
2. Description of the Related Art
Obesity is an excess of body fat usually due to changes of physiological or biochemical function and is a significant impairment of health. Fat usually contains neutral lipids, phospholipids and cholesterols. Weight gain is dependent on a person's energy intake being greater than energy expenditure. There are two types of obesity: (a) simple obesity, and (b) secondary obesity. Simple obesity is divided into idiopathic obesity and acquired obesity; the latter accounts for more 95% of obesity. Idiopathic obesity results from a large number of fat cell, and is usually found in childhood obesity. Acquired obesity results from a larger size of fat cell, and is usually found in adult obesity. Secondary obesity is known as symptomatic obesity, usually results from endocrine or metabolic diseases. Obesity is associated with several chronic diseases, such as diabetes mellitus, cardiopathy, hypertension, apoplexy, biliary calculus, gout, and some carcinomas.
There are five strategies for treating obesity: diet, exercise, behavioral treatment, drug treatment, and therapeutic operation. The strategies are chosen or combined to treat an obesity patient depending on the patient's risk factors in health, and the rate and effect of losing weight, which are influenced by multiple factors such as age, height, family history, and risk factors. The mechanisms of drug treatment include inhibiting appetite, increasing energy expenditure, stimulating fat movement, lowering triacylglycerol synthesis, and inhibiting fat absorption. Examples of these drugs are phenylpropanolamine (PPA), orlistat (Xenical™), and sibutramine (Reductil™). However, it is a new trend to treat obesity with a natural substance, not a drug.
In the prior art, it was found that some microorganism strains could be used to treat obesity, or complications thereof. For instance, Lactobacillus gasseri SBT0270 was found to have an ability to lower cholesterol concentration related to deconjugate of bile acid (Usman, B. and Hosono, A. (2001) Hypocholesterolemic effect of Lactobacillus gasseri SBT0270 in rats fed a cholesterol-enriched diet. J. Dairy Res. 68: 617–624). The mechanism of treating obesity is lowering the solubility of the deconjugated bile acid through absorption of free form of bile acid by L. gasseri an exhaustion with stools (since the exhausted bile acid cannot be recycled back to the liver, and new bile acid is needed to be synthesized from cholesterol.) Besides, it was found that L. gasseri could be combined with bile acid and cholesterol to make an excretion.
Lactobacillus rhamnosus was regarded as a potential probiotic lactic acid bacterium that has an immune-enhancing property. Safety assessment of L. rhamnosus was also investigated. Zhou et al. disclosed that hematological parameters (red blood cell and platelet counts, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration); differential leukocyte counts; blood biochemistry (plasma total protein, albumin, cholesterol, and glucose); mucosal histology (epithelial cell height, mucosal thickness, and villus height); and bacterial translocation to extra-gut tissues (blood, liver, spleen, kidney and mesenteric lymph nodes) of mice administrated with L. rhamnosus showed similar profiles to those of the control mice (Zhou, J. S., Shu, Q., Rutherfurd, K. J., Prasad, J., Birtles, M. J., Gopal, P. K. and Gill, H. S. (2000) Safety assessment of potential probiotic lactic acid bacterial strains Lactobacillus rhamnosus HN001, Lb. acidophilus HN017, and Bifidobacterium lactis HN019 in BALB/c mice. International Journal of Food Microbiology 56: 87–96). In addition, Agerholm-Larsen et al. disclose that administration of a yogurt fermented with L. rhamnosus does not change low density lipoproteins (LDL)-cholesterol. On the other hand, only systolic blood pressure was significantly reduced (Agerholm-Larsen, L., Raben, A., Haulrik N., Hansen, A. S., Manders, M., and Astrup A. (2000) Effect of 8 week intake of probiotic milk products on risk factors for cardiovascular diseases. Eur J Clin Nutr. 54(4): 288–97). Accordingly, the conventional L. rhamnosus strain is evidenced that it does not change plasma total cholesterol and LDL-cholesterol. Furthermore, no body weight change is observed when administration of the conventional L. rhamnosus strains.